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Entry  Wed Feb 13 19:09:32 2013, yuta, Summary, General, possible explanations to oval REFL beam REFL_1044844506.bmp
    Reply  Wed Feb 13 19:30:45 2013, Koji, Summary, General, possible explanations to oval REFL beam 
       Reply  Wed Feb 13 19:41:07 2013, yuta, Summary, General, possible explanations to oval REFL beam 
    Reply  Wed Feb 13 22:09:26 2013, Jenne, Update, Alignment, REFL is not clipped 
       Reply  Thu Feb 14 00:10:12 2013, yuta, Summary, Alignment, REFL is not clipped 
          Reply  Thu Feb 14 10:42:41 2013, Jamie, Summary, Alignment, MMT, curved TTs does not explain beam ellipticity at Faraday T.pdfS.pdf
Message ID: 8082     Entry time: Thu Feb 14 00:10:12 2013     In reply to: 8081     Reply to this: 8084
Author: yuta 
Type: Summary 
Category: Alignment 
Subject: REFL is not clipped 

Let's wait for astigmatism calculation.
In either case(clipping or astigmatism), it takes time to fix it. And we don't need to fix it because we can still get LSC signal from REFL.
So why don't we start aligning input TTs and PRMI tomorrow morning.

Take the same alignment procedure we did yesterday, but we should better check REFL more carefully during the alingment. Also, use X arm (ETMX camera) to align BS. We also have to fix AS steering mirrors in vacuum. I don't think it is a good idea to touch PR2 this time, because we don't want to destroy sensitive PR2 posture.


Calculations need to be done in in-air PRMI work:
  1. Explanation for REFL astigmatism by input TTs (Do we have TT RoCs?).
  2. Expected g-factor of PRC (DONE - elog #8068)
  3. What's the g-factor requirement(upper limit)?
    Can we make intra-cavity power fluctuation requirement and then use PRM/2/3 angular motion to break down it into g-factor requirement?
    But I think if we can lock PRMI for 2 hours, it's ok, maybe.
  4. How to measure the g-factor?
    To use tilt-and-measure-power-reduction method, we need to know RoC of the mirror you tilted. If we can prove that measured g-factor is smaller than the requirement, it's nice. We can calculate required error for the g-factor measurement.

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